1. Field of the Invention
The present invention relates to a multi-layer ceramic capacitor or varistor adapted to be mounted on the surface of a circuit board. In particular, the invention relates to a square chip design for a capacitor or varistor for mounting on an electronic circuit board with corner terminations. More precisely, the present invention relates to a symmetrical multi-layer capacitor or varistor chip design for mounting on a circuit board to act as a filter therefore, with corner terminations and unoriented feed-thrus placed diagonally across the chip.
2. Description of the Prior Art
With today's push toward miniaturization, Electromagnetic Interference (EMI) could potentially render a circuit useless or worse still it could cause an incorrect answer to be generated from a computer by randomly powering a gate up or down. As a result filtering out undesirable signal noise (i.e., unwanted frequencies) has become a major design consideration for new electronic devices.
To solve this problem, designers have used capacitors and varistors for some time. Additionally they have been using specifically design electrical devices known as feed-thru filters to specifically solve these problems. Feed-thru filter devices are well know in the art. They have been used in everything from cellular phones and laptop computers to implantable medical devices such as cardiac pacemakers. Their primary function is to attenuate undesirable or transient voltage frequencies or EMI from a signal passing through a circuit. They can be either capacitor- or varistor-based devices.
There are two primary capacitor/varistor geometries in use in the industry--the rectangular chip and the discoidal chip. The monolithic or multi-layer rectangular chip configuration is produced in very high volumes in highly automated facilities around the world. One example of such a rectangular chip is disclosed in commonly owned U.S. Pat. No. 5,880,925 entitled "Surface Mount Multilayer Capacitor."
In many instances, a chip requires a significant amount of care be exercised during the manufacture, packaging, and installation of the chip. Sometimes a chip requires additional machinery or man-hours to ensure that the chip is oriented properly throughout the manufacturing process.
The termination process is the widely-used industry process in which chips are oriented to form the terminals on the sides of the chip and then re-oriented to form the terminals on the ends of the chip. The electrically conductive terminals allow for electrical connection between the lead structures of the electrode plates and the circuitry in which the chip is ultimately placed.
The complete disclosure of U.S. Pat. No. 5,880,925 (including all figures and discussion thereof) is fully incorporated herein by reference.
Additional United States Patents provide examples of capacitor-based feed-thru filters for use in attenuating undesired signal frequencies. Examples include U.S. Pat. Nos. 3,255,396; 3,320,557; 3,426,257; 3,989,988; 4,747,019; 4,908,590; 5,097,389; 5,650,759; and 5,595,829. The complete disclosures of all such patents (including all figures and descriptions thereof) are fully incorporated herein by reference.